Pet owners are often faced with the unpleasant task of removing and cleaning pet excrement from litter boxes and the like. Constant attention must be devoted to keep litter boxes clean in order to eliminate odor, health problems due to poor sanitary conditions, and avoid soiled carpets or furniture. Efforts to provide conveniently cleanable litter boxes for small animals still leave much to be desired in one respect or another.
It is known that household pets such as cats will refuse to use a sanitary litter box which has been soiled by solid excrement; cats will invariably attempt to "dig" around the soiled area, strewing litter about, or will seek other locales for relief. However, it is also known that urine-soiled sanitary litter which does not contain solid excrement will be reused to a certain degree. Of course, when the litter has become badly urine-soiled, the animal will refuse to use the litter box as well.
It is desirable to exploit this characteristic of limited reusability of sanitary litter to the extent possible for purposes of economy and convenience of the pet owner. For example, U.S. Pat. No. 4,217,857 to Geddie discloses one approach for separating excrement from sanitary litter wherein the solid excrement is removed by lifting a screen pan, sifting the pet litter from the screen pan, and disposing of the solid excrement. In another approach, U.S. Pat. No. 3,100,474 to Schneider, a slidable imperforate plate is removably mounted in the box that contains the litter, and when the plate is removed from the box, the litter falls downwardly onto and through a screening member which permits litter to pass through but which catches the solid excrement. While both of these prior art approaches permit relatively easy separation and collection, both include a separate screen element which requires pouring of the litter from one place to another in preparation for reuse, thereby risking spills and undesirable contact with the soiled litter.
In another approach, illustrated in U.S. Pat. No. 4,325,325, pouring of the litter from place to place is not required, but the entire unit must be inverted and shaken to separate the litter from the excrement. This can be difficult for the elderly or others whose frailty precludes lifting and inversion.
There is accordingly a need for a simple, inexpensive, and easy to manufacture pet litter box which is easy to clean and which permits convenient separation of excrement from litter without requiring pouring of soiled litter from place to place or inversion of the entire litter box.